Call the cops. You sound like you handled this much more civily than I would have. Think of the example he is teaching his child.
Next time you could (this is purely hypothetical
) take your fist and bang on the side of his car, then demand to know why he hit you by riding so close and tell him you are calling the cops for an accident report. Probably put him in a state of panic when he knows you are legally on the road.
Of course, these days w/ road rage it could also turn into a violent confrontation, so I don't recommend this. Just like thinking out loud sometimes.